1. Field of the Invention
The present invention relates to a door locking device for a vehicle.
2. Description of the Prior Art
Door of a vehicle is pivotally installed on the vehicle body by means of a door hinge attached on the vehicle and a corresponding hinge attached to the door. A door latch installed on the door is engaged with a door striker attached on the vehicle body to maintain the door closed with respect to the vehicle body, and the door latch is interconnected with door handles.
The door handles consist of an inside handle and an outside handle. A safety knob provided on an inside of the door makes it unable to open the door from outside of the vehicle.
In order to open the door from inside of the vehicle when the safety knob is locked, one must unlock the safety knob first and, then, pull the inside handle. To simplify this two-stepped operation, it is necessary to let the safety knob unlocked automatically by pulling the inside handle without releasing the safety knob separately.
A door locking device with such function is disclosed in a Laid-Open Japanese Patent Application No. 5-321518, the brief composition of which being shown in FIG. 4. Referring to FIG. 4, the inside handle 51 interconnected with the door latch (not shown) by a rod 52 is pivotally installed by a pin 50, and the safety knob 55 interconnected with the door latch by a rod 57 is pivotally installed by a pin 56. One end of a rod 53 is connected with the inside handle 51, and the other end of the rod 53 is engaged with a slot 54 formed on the safety knob 55.
When the inside handle 51 is pulled along the direction A, the rod 53 become pushed along the direction C to turn the safety knob 55 along the direction D and, accordingly, the rod 57 become pulled along the direction E to unlock the door latch, and, simultaneously, the rod 52 become pulled along the direction B to release the engagement between the door latch and the door striker. Thus, it is not necessary to release the safety knob 55 separately to unlock the door latch because unlocking of the door latch and releasing of the engagement between the door latch and the door striker can be simultaneously performed by pulling the inside handle 51.
However, in the above-mentioned door locking device, the operation of unlocking of the door latch by moving the rod 57 interconnected with the safety knob 55 and releasing of the engagement between the door latch and the door striker by moving the rod 52 interconnected with the inside handle 51 are performed simultaneously, not sequentially, and these two operation may interfere with each other such that the operation of the door latch may be paralysed.